OFFSET
1,3
COMMENTS
Column 1 of A209969.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 16*a(n-1) - 83*a(n-2) + 132*a(n-3) + 56*a(n-4) - 88*a(n-5) - 32*a(n-6).
Empirical g.f.: 9*x^2*(1 + 2*x) / ((1 - x)*(1 - 4*x)*(1 - 5*x - 2*x^2)*(1 - 6*x - 4*x^2)). - Colin Barker, Jul 14 2018
EXAMPLE
All solutions for n=4:
..0..1....0..1....0..0....0..0....0..0....0..0....0..0....0..0....0..1
..1..0....0..0....0..0....0..0....1..0....0..0....1..1....0..1....0..1
..1..1....2..2....1..1....1..1....0..0....1..1....2..1....0..0....0..0
..2..2....2..3....2..2....2..2....2..2....2..2....2..2....2..2....2..2
..2..3....2..2....3..3....3..2....2..3....2..3....2..3....2..3....2..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 16 2012
STATUS
approved